Simple Organisms

Simple Organisms are viruses and one-celled organisms, such as bacteria, blue-green algae, and protists. Viruses are on the borderline between living and nonliving things. They are not true cells but simply genetic material surrounded by a protein coat. Viruses do not show life activities unless they are inside a living cell. They use their host's DNA to reproduce. Viruses cause many plant and animal diseases; unless the organism can protect itself, the virus spreads to cause illness and even death.

1. What are simple organisms?

2. Are viruses living or non-living things?

3. What for do they use some other organism?

4. Can viruses spread very rapidly and cause diseases?

Read the text and say if the sentences are true or false; correct false sentences.

Invertebrates

Soft-bodied invertebrates (animals without a backbone) include the sponges, jellyfish, slugs, and all the different kinds of worms. They have a soft body that is not protected by a hard outer skeleton. The most primitive of the soft-bodied invertebrates are the sponges – simple internal skeleton. Some soft-bodied invertebrates are protected by a shell. They are made up of cells supported by For example, snails, clams, and oysters each have one or two shells to protect them from predators and from drying out when they are out оf water.

1. Soft-bodied invertebrates don’t have any skeleton.

2. Some of them have shells.

3. Shells protect them from predators.

Read the text make up its plan and answer the questions.

What types of bacteria do you know?

Bacterium, plural bacteria, any of a group of microscopic organisms that are prokaryotic, i.e., that lack a membrane-bound nucleus and organelles. Bacteria are unicellular (one-celled) and may have spherical (coccus), rod-like (bacillus), or curved (vibrio, spirillum, or spirochete) bodies. Different bacteria inhabit virtually all environments, including soil, water, organic matter, and the bodies of eukaryotes (multicellular animals). Some bacteria are known to be beneficial to humans and the higher animals, while many others are harmful; bacteria are the chief cause of infectious diseases in humans.

<== попередня сторінка	\|	наступна сторінка ==>
CORAL REEFS	\|	What kind of cell walls do they have?

Не знайшли потрібну інформацію? Скористайтесь пошуком google:

Генерація сторінки за: 0.004 сек.